BOSTON — Tampa Bay forward Sean Bergenheim is “doubtful” for tonight’s Game 7 of the Eastern Conference Final at the TD Garden, according to Lightning head coach Guy Boucher.

Bergenheim was injured in the first period of Game 5 last Monday and has not returned to game action since. He skated this morning during an option on-ice session for Tampa Bay.

“I wouldn’t say optimistic for now. It’s better. He might try the warm-up,” said Boucher, who’s never going to rule a player in or out until game time at this time of year. “We’ll see. I’ve still got to talk to my therapists and doctors. There’s been some improvement. So to what extent, we’ll have to wait and see, but doubtful.”

Without Bergenheim, the Lightning have had to do even more line juggling than usual. The Bergenheim-Dominic Moore-Steve Downie line had been one of their better trios throughout the playoffs, with Bergenheim scoring nine goals (two vs. the Bruins) in 16 postseason games.

“Well, obviously you want to think of your own team. But at the same time, when you look at the Bruins’ depth, it does make a difference because instead of equalizing things, it has a tendency to give them a little upper hand on that, because they’ve got [Tyler] Seguin on their third line and [Michael] Ryder. And [Chris] Kelly is doing really well,” said the Lightning coach. “And they’ve got [Rich] Peverley on the fourth line. [A] first-line guy from another team on their fourth line, and that’s where Bergenheim became extremely important for us in the previous series and this series where the line with Downie and Moore played like a first line.

So right now, we’re trying to find chemistry with some other guys. I tried things two games ago. I tried things the last game. Some of it worked, some of it didn’t work. It makes me juggle a little bit to try to find some chemistry that is absolutely crucial in any of these playoff games.”